Carburetor



May 21, 1935; v w, H, WEBER l cmauamon Fi led April 6,- 1929 2 Sheets-Sheet 2' 30 min 44W Patented May 21, 1935 UNITED STATE CABBURETOR Walter H. Weber, Detroit, Mich., assignor to Detroit Lubricator Company, Detroit, Mich., a corporation of Michigan Application April 6, 1929, Serial No. 352,968

31 Claims.

My invention relates to new and useful improvements in carburetors, and more particularly to a carburetor of the plain tube type.

An object of my invention is to provide a carburetor which will supply a proper combustible Another object is to provide means to prevent decrease in the. richness of the fuel mixture during intermediate engine speeds for the warming-up of the engine.

The invention consists in the improved construction and combination of parts, to be more fully described hereinafter, whereby proper fuel mixture may be supplied to an internal combustion engine, and the'novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specification, I have fully and clearly illustrated a preferred embodiment of my invention, in which drawings- Figure l is a view in side elevation of my improved carburetor;

Fig. 2 is a top plan view thereof, partially in horizontal section;

Fig. 3 is a view thereof in longitudinal ver tical central section;

Fig. 4 is a view in partial vertical section on the line L-l of Fig. 2;

Fig. 5 is a top plan detail view of the bottom part of the carburetor, and I I Fig. 6 is a detail view in vertical section on the line 6-6 of Fig. 2.

Referring to the drawings by characters of reference, I designates, generally, a carburetor casing, preferably comprising a bottom part or section 2 and a top part or section 3, which are joined together by studs 3', or the like, on a substantially horizontal plane, and which are preferably die-cast, though it is of course apparent that any other suitable method of forming the sections may be employed. In the section 2 are an air chamber 4 and a liquid fuel reservoir or constant level float chamber 5, which are separated by a wall 6 in' which are a plurality of substantially vertical wells or chambers I, 8 and 9,of which the chamber I is open to the float chamber 5 and serves as a valve chamber therefor. Each of the chambers 4, 5, I, 8 and 9 is ope at its upper end. Secured to the under side'o the section 2, in any suitable manner, beneath the float chamber 5, is a cup-like member I0 which cooperates with a downward open recess II in section 2, to form a strainer chamber having an inlet passage l2 terminating in a nipple I3 for connection to a source of liquid fuel supply and having a passage I4, see Fig. 4,

, in the bottom wall of section 2, and which terminates preferably centrally beneath the valve chamber I. Clamped between the member I0 and section 2, is a; filter medium I5, preferably a wire strainer of fine mesh which separates the passages l2 and It. The chamber I connects with passage It by a substantially vertical passage I6, which at its top is of enlarged diameter and'internally threaded, as at l1, to receive the lower end of a sleeve member l8 which is screwthreaded therein. Through the sleeve adjacent its lower end are ports I9 which open into chamber I, and below these ports I9 the sleeve has an intema-l annular shoulder 20 serving as a valve seat. A needle valve 2| cooperates with seat 20 to close the inlet passage I6, and has a stem 22 guided for reciprocation in the sleeve l8. The valve '2! is adjustably supported, as by threaded engagement with a. collar 23 which hangs in the arms of a yoke 24 at one end of a float lever 25 which is pivotally supported on a bearing pin 26 secured in the wall of the casing I. Rigid with the other end of lever 25 is a float member 21, preferably a hollow sealed sheet-metal body.

Within the air-chamber l is a vertical boss or web member 28 which rises from the bottom wall of the air chamber and extends from the wall 6 beyond the vertical center line of the air chamber. Through the Webmember 28 is a vertical bore 29, substantially coaxial with the center line of the air chamber and which is constricted at its 'upper end to provide a downward facing shoulder 30 below which the bore 29 is internally threaded, as at 3I. The bottom end of bore 29 is sealed by a plug member 32. Between the bore 29 and the bottom of the float chamber 5 is a fuel feed conduit or passage 33. Projecting vertically upward from the boss 28 to a point slightly above the normal liquid level line L-L, is a fuel discharge nozzle or tube 34 which has a circum- W ferential flange 35 adjacent its lower end which engages the shoulder 36. Abutting the under portion 65 at an angle to portion 64.

side of flange 35 and surrounding the tube 34, is a ring or sleeve member 36 which seats on a plug member 31 threaded into the bore 29 and serving to force the flange 35 against the shoulder 30.

and to tightly clamp and seal member 36 between member 31 and the tube 34. Through plug member 31 is a port 38 concentric with bore 29, and which is calibrated to provide the main liquid fuel supply jet or inlet for the carburetor. Through the ring member 36, is a port 39 which is calibrated to regulate the degree of sub-atmospheric pressure which acts on the main jet 38.. From the bottom of the well or chamber 8 which is of reduced diameter to provide an upwardfacing shoulder 40, a passage or conduitM leads through the boss 28, to the bore 29 at themember 36 for communication with port 39. This port 39 also serves as a fuel inlet from the chambers 8, 9 to the-mixing chamber and provides a supply of fuel which is supplemental to the supply of fuel from the main fuel inlet or jet 38. Between the bottom of chamber 8 below shoulder 49 and the bottom of the chamber 9, is a passage or port 42. Within the chamber 8 is a tight fitting plug member 43, which seats on the shoulder 49 and hasa longitudinal bore 44 therethrough. At its upper end the member 43 has a circumferential end recess 45 which provides, with the wall of chamber 8, an annular reservoir or chamber. The member 43 extends upward preferably slightly beyond the bottom section 2, and the recess 45 extends downward substantially to the line L-L of the normal liquid .fuel level. In the section 2 and concentric with the chamber 9 is a vertical bore 46 which is of reduced diameter, as at 41, at its inner 'or upper end, which opens into chamber 9 to provide a valve port for a purpose to be described. The bottom end of the bore 46 is closed and sealed by a plug member 48 having an upward or inwardly open cylindrical longitudinal recess 49 of a diameter larger than port 41. Connecting the bore 46 below port 41 with the passage 33, is a passage or conduit 59 by which liquid fuel 'may be supplied to the chambers 8 and 9 from the carburetor of' liquid fuel. The air chamber 4 is supplied with air by an air inlet passage or conduit 53 having its longitudinal center line substantially horizontal. Extending across the air inlet 53 is a substantially horizontal shaft 54 which projects through the walls of the conduit 53 and is journaled therein. Fixed rigidly on the shaft 54 within the conduit is a disc member 55 comprising an air control or choke valve whereby the ratio of fuel to air may be controlled. Rigid with one end 55 of shaft 54, is a lever arm 51 having securing means 58 for the end of a valve operating rod or wire (not shown) by which an operator may regulate the position of valve 55. A support and guide member 59 for the rodor wire may be secured to the casing I, if desired. Rigid with the other end 69 of the shaft 54, is a cam member 6|, fora purpose to be described, having a cam groove 62 in its periphery. The base of the groove 62 is arcuate at one end, as at 63, and merges into a straight portion 64 tangent thereto which terminates in a straight outside of the casingl at the upper end of the chamber 9, is a boss 66 which extends outward substantially to the plane of the groove 62. Journaled on a pin or screw 61 projecting from On the boss 86, is a lever member 68, preferably a bellcrank, one end 69 of which extends into the groove 92 so that rotation of the cam member 6| will depress the end 69 of the lever. Atits opposite end the lever 68 has an arm portion 79 which extends upward and then substantially horizontally inward over chamber 9. A spring means H having one end secured to the casing I and the other end secured to the lever 68 normally acts to maintain the lever end 69 in contact with the base of the cam groove 62.

The top section 3 overlies the chambers 4, 5, l, 8 and 9 and has a cover portion 12 for the reservoir 5 and chambers I and 9, and a portion 13 extending upward therefrom which has a substantially vertical cylindrical bore 14 therethrough concentric with the nozzle 34 and forming the mixture outlet 14'. Through the cover portion 12 is an air inlet port 12' opening intothe reservoir 5 above the normal fuel level to maintain atmospheric pressure on the fuel therein. A dirt shield 13 may be provided to prevent foreign matter from entering the port 12'. Within the bore 14 and extending downward into the top of the chamber 4 to a point below the top of nozzle 34, is a choke tube or venturi 15, which forms the lower part of the carburetor mixing chamber 16, as is well known in the art. The Venturi tube 15 is preferably held in position by a set screw 11, or the like, threaded through the casing I and having a lock nut 18. At the bottom of the annular recess or reservoir 45 is a port 19 in the side wall of chamber 8, which alines with a port 89 in the tube 15 and which is slightly above the most constricted portion of the venturi. Projecting substantially horizontally into the venturi or mixing chamber and seated and sealed in the port 80, is a discharge tube 8| having a calibrated discharge aperture 82. Extending diametrically across the bore 14 above tube 15 and preferably substantially in the vertical plane of the longitudinal center line of the air inlet 53, is a shaft 83 which is journaled in the walls of portion 13, and the ends of which project therefrom. Fixed on the shaft 83 to turn therewith, is a disc member 84 within the bore 14 and which serves as a throttle member to control the sub-atmospheric pressure in the mixing chamber and the discharge of mixture therefrom. Rigid with that end of the shaft 83 which overlies the air inlet 53, is a lever member 85 having stop arms 85 which cooperate with a boss or abutment 81 projecting from the portion 13 to limit the rotation of the shaft 83 to substantially seventy-five degrees. The arm 86 which limits closing of the throttle valve is preferably provided with an adjustment means 88, such as a screw threaded therethrough and held in adjusted position bymeans of a lock screw 88'. Journaled or pivoted on the opposite end of the shaft 83 is a lever arm 89 which extends to a point substantially centrally over'the chamber 9. Rigid with the shaft 83 and on the end thereof beyond arm 89, is an operating member 99 having a finger or lug 9| which extends beneath the arm 89 so that rotation of shaft 83 to move the throttle valve 84 toward closed position will raise the arm 89 while opening of the throttle valve will allow downward movement of the arm 89. Through the cover portion 12 is an aperture 92 registering with chamber 9. Around the aperture 92 the bottom face of the portion 12 is recessed to provide a downward facing shoulder 93 for cooperation with a peripheral flange 94 on a hollow cap member 95. The body of the member 95 projects upward through the aperture 92 and the shoulder 93 clamps the flange 94 tightly against the section 2. Through the top wall of the member 95 is a slot 96 transverse to the axis of shaft 93. Within the chamber 9 is a piston 91 which is connected to the free end of arm 99 by a rod or link which passes freely through slot 99. The under or working face of the piston 91 is just above the plane of the normal liquid level when the throttle is in idle position (see Fig. 4). Positioned between the piston 91 and the top wall of member 95, is an expansion member 99, preferably a coil spring under compression and, which surrounds rod 90. a

Spring. normally urges the arm 09 into engagement with lug 9| and tends to move the piston 91 downward. In the rod or link 99 is a notch I00, which when the piston 91 is in its uppermost positiori, i. e., with the throttle valve substantially closed, will be above the cap member and in cooperable relation to the horizontal lever arm portion 10, so that when the air choke valve 55 has been moved more than one-quarter toward closed position, spring 1I will force arm 10 into the notch I00 to prevent downward movement of piston 91. Depending centrally fromthe piston 91 is acontrol means, preferably a cylindrical member IOI of a diameter substantially equal to the diameter of the valve port 41, so that the member IOI will have a tight sliding fit therein to effectively seal the port 41. The lower end .of member IOI extends into port 41 when the piston is in its uppermost position, i. e., throttle in idle position, and has a bevel or conical taper, as at I02,

to permit a predetermined flow through jet 41. The taper I 02 preferably starts at about one sixty-fourth to one thirty-second of an inch above the valve port 41 and the bottom of chamber 9. The member IN is hollow, having a bore I03 which is closed at its ends. At the lowerv end of bore I03 and just above the taper I02, is an inlet port I04 to the bore I03, and at the upper end of the bore I03 is an outlet port I05 into the chamber 9. The length of the port or jet 41 is such that the inlet port I04 will be cut off until the throttle valve has been opened a distance corresponding to a level road car speed of fifty miles or more per hour. When the throttle valve passes beyond such a position, the member IOI will have been depressed sufliciently to carry the port I04 below the wall of port 41, so that fuel will flow .under the gravity head in the float chamber 5 to bore 46 through port I04, bore I03, and port I05 into chamber 9, providing a submerged fuel jet. In the side wall of the chamber 9 at its upper .end, is a slot I06 open to the atmosphere, which terminates at a point slightly below piston 91 to insure atmospheric pressure on the liquid in chamber 9 when the piston is in position corresponding to idle, and to permit the well 9 to fill rapidly when the throttle is in idling position. Over the middle chamber 8 is a boss I01 which rises from portion 12 and extends laterally from portion 13. In the boss I01 is a substantially cylindrical chamber I08, closed at its upper end, and which alines with and forms the upper end of chamber 8. Through' the boss I01 is a passage I09 connecting-the upper end of chamber 9 with the interior of the float chamber 5 above the liquid level to maintain atmospheric pressure in the chamber 8. Through the boss I01 above chamber I09 is a bore IIO which is transverse to the shaft 03. In the bore H0 is an annular shoulder III forming a valve port beyond which the bore H0 is threaded to receive the threaded stem of a needle valve II2 which controls the area of the port III. A spring means II3, preferably a coil spring, surrounding the stem of valve III is held under compression between a head II4 on the stem and the boss I 01, to hold the valve III in adjusted position. A boss II5, substantially in the horizontal plane of bore IIO, extends externally for substantially ninety degreesaround the portion 13. Through the boss 51s a passage or conduit I I9 communicating at one end with the bore I I0 beyond valve seat I I I and at its other end opening into the mixture outlet 14' (see Fig. 6). In the end of passage II5 which communicates with bore 14, is a plug member II1 having a calibrate'd discharge port Ill therethrough. Through the upper end wall of chamber 0 is a vertical aperture II! which opens into the bore I I0 beyond the valve seat I I I. Seated in the aperture H9 and depend'ng from theupper end wall of chamber 8 is a tube I20 which extends through the bore 44 of member 43 in spaced relation to the side wall of the bore to provide an annular air passage. The tube I20 terminates below the passage 4| substantially at the bottom of chamber 9 and has a calibrated-inlet port III in this bottom end.

The operation of my carburetor is as follows: When it is desired to start the engine (not shown), to which the carburetor is attached, the air inlet choke valve 55 is rotated to close the, air inlet 53 by meansof the usual dash control (not shown) connected to the lever 51 which is fixed on the choke valve shaft 54 which will increase the ratio of fuel to air for engine starting. The cam member III which is fixed to the opposite end of the choke valve shaft rotates with the latter, and during the first approximately quarter rotation counterclockwise of Fig. 1, i. e., toward valve closing position, releases the end 59 of hellcrank lever 69, permitting the spring means 1| to rotate lever 58 counterclockwise to cause the substantially horizontal end portion 10 to engage in the slot or notch I00 inthe pump piston link 98 to prevent the latter, and hence the piston 91,

from moving downward as the throttle valve 04 is opened. The throttle valve is then opened slightly beyond idle position and the engine is ready to be started in the usual manner. The high sub-atmosphere pressure created in the mixing chamber 15 with the air inlet 53 thereto closed, when the engine ls turned over, draws the desired quantity of liquid fuel from the main and idling nozzles 34, 'I I8, respectively, together with a little air from the idling air bleed III, to supply the desired overrich mixture for engine starting. As soon as the engine fires the air inlet choke valve 55 is opened partially, enough to supply suflicient air to dilute the overrich starting mixture to keep the engine running, the .quantity of air depending upon the atmospheric and engine temperatures and the requirements of the engine. The richness of the f warming-up mixture depends upon the 'quantity of air supplied to the mixing chamber 15, which is regulated by the position of the air inlet choke valve 55, and the average operator is soon adept in locating the proper choke valve position. As long as the choke valve 55 is maintained in any effective partly choked position (that is, more than approximately one-quarter closed), the lug or dog portion 10 on the bell-crank lever 50 remains .engaged in the notch I00 of the pump piston link 99, thereby keeping the pump disengaged from actuation by the throttle .valve 34. The pump piston 91 throughout the starting and fwarm- .ing-up operations of the carburetor remainsin its uppermost position, as shown in Fig. 4, and

thereby keeps the pump chamber fuel supply orifice or jet 41 open, and hence causes the jet 41 to feed an additional amount of fuel, which is constant in quantity'per unit of time, to the main nozzle 34 via the bottom of chamber 9, port 42, bottom of chamber 8, passage 4! and orifice 39. During these starting and warming-up operations the pump chamber 9 being open to atmosphere, cooperates with the chamber 8, also open to atmosphere, to provide an atmospheric fuel well of the. desired capacity, the chamber 9 compensating for the decreased volumetric capacity of chamber 8, due to the sleeve 43, so that the chambers 8 and 9 together comprise the atmospheric leg of a U-shaped passage or conduit having the nozzle discharge tube 34 as the other or fuel leg thereof, and which legs are in communication by reason of the passage 4I so that the passage leg 8, 9 and the passage leg 34 function as a U-tube. The additional feed or discharge of liquid fuel from the atmospheric well or leg of the U-shaped passage (chambers 8 and 9) is constant in quantity per unit of time, thereby enriching the main fuel mixture inversely as the speed of the engine. When the engine hasbecome suificiently warm, which will be apparent from its performance, the choke valve is returned to its normally open position, as in Fig. 3, rotating cam 6I clockwise of Fig. 1 to depress end 69 of the bell-crank lever 68, thereby to disengage lever portion 10 from the notch I'00 in the pump piston link, restoring the pump piston 91 to control by the throttle valve 84 and permitting it to function normally.

In the event the operator opens his throttle valve 84 before he closes the choke valve 55 for starting, the bell-crank lever lug portion 10 will bear laterally against the pump piston link 98, due to the spring means 1I acting on the bellcrank lever, and the lug or dog portion 10 will engage in the notch I00 ofv the link only when the throttle valve 84 is returned to idle position. It may be noted that the position of the pump piston 91 does not affect engine starting in any way, as is apparent, and since the throttle valve 84 is soon returned to idle position after the engine fires the sequence in which the operator closes choke valve 55 and opens the throttle valve 84 is of little importance.

As the throttle valve 84 is gradually opened from idle position to speed up the engine, the throttle shaft lug=9I will be moved downward, permitting the piston spring 99 to move the piston 91 downward and the tapered valve I02 carried thereby. As the piston valve I82 is moved downward, it will decrease the quantity of fuel admitted to the chambers 8 and 9, thereby causing alowering of fuel level in the chambers, de-

creasing the working head and decreasing the richness of the supplementary mixture supplied through'the idling jet II8 as the richness of the mixture supplied through the main jet 34 increases. At a throttle opening corresponding to a level road car speed of substantially fifteen miles per hour, the piston valve I02 will have cut off the fuel inlet port or jet 41 to the pump chamber 9, and the well, comprising chambers 8 and 9, will be emptied. During the period of throttle opening when the inlet 41 to the pump chamber 9 is cut off by member IOI, atmospheric air entering the top of the chamber 8 via passage I09 from the reservoir 5, will pass down through bore 44 around the idling tube I20, through the calibrated jet 39 at the end of the horizontal passage H and into the bore of .the main nozzle 34, so that an emulsion of air and fuel will be formed above jet 38 and issue from the main nozzle 34 to the mixing chamber 18. This emulsion, which increases in quantity of liquid fuel relative to air as the throttle valve is opened, will provide a proper and economical mixture for all car speeds and loads corresponding to all level road car speeds below fifty miles per hour. The fuel inlet port 41 to the pump chamber 9 will remain closed by the piston valve member IOI until the throttle valve 84 has been opened to a position corresponding to fifty miles per hour level road car speed. For all throttle valve positions corresponding to level road car speeds above fifty miles per hour, the inlet port I04 will have been moved downward so that it will be below the wall of the inlet port 41, and liquid fuel will flow through port I 04, through the hollow bore I03, and from the outlet port I05 into the pump chamber 9, thus constituting a submerged fuel jet. The liquid fuel from this submerged jet will flow through port 42 into chamber 8 and be fed as an emulsion by the air entering the top of the chamber 8 from reservoir 5, through the calibrated jet 39 to the bore of the main nozzle 34. This additional supply of fuel from inlet 39 supplements the supply from inlet 38 to the main nozzle and is dependent entirely upon the throttle position and enters the nozzle as an emulsion to increase the richness of the mixture fed to the engine at level road car speeds above fifty miles per hour and for all throttle openings required to develop maximum power regardless of car speed.

So much of the operation as has been described has not dealt with the problem of obtaining punch i. e., rapid acceleration. For level road car speeds of about fifteen miles per hour or more, the engine has sufiicient momentum to accelerate rapidly upon a quick opening of the throttle without the necessity of enriching the fuel mixture; but for car speeds below fifteen miles per hour some means must be employed to obtain the necessary enriched mixture to give punch. This problem has been solved by employing the pump piston 91 operating in the atmospheric leg of the U-shaped passage. With the car travelling at a speed below fifteen miles per hour so that chambers 8 and 9 are filled or partially filled, and with the lug 10 disengaged from notch I00, quick opening of the throttle valve 84 will permit spring 99 to expand, forcing piston 91 downward to expel the liquid fuel from chamber 9 through port 42. Since normal operation to obtain rapid acceleration would be to quickly open the throttle valve 84 to its maximum open position, the piston 91 will force all of the fuel in chamber 9 into chamber 8, and due to plug or sleeve 43, the major portion of this shot of solid liquid fuel which is not forced by the piston through port 39 into the main nozzle 34, will overflow the top of plug 43 and be caught in chamber 45. The chamber 45 is open to atmosphere by reason of passage I09, so that the quantity of liquid fuel caught in chamber 45 will flow under the difference of pressures and by gravity head through the nozzle 8| and calibrated port 82. Since the port 39 is relatively small, very little of the fuel discharged from chamber 9 will be forced therethrough, and the port 82 is calibrated so that this additional fuel for acceleration fed to chamber 45 and discharged therefrom into the mixing chamber 16, will be prorated over as long a period of time as possible, consistent with the desired enrichment of the fuel mixture.

'It is to be noted that when inflow of fuel to "chamber 9 is cut off by opening of throttle valve 84, fuel will not be trapped in the chamber 9, due to cut-01f of the passage I 05 by piston 91, because the piston 91 intentionally does not fit tightly enough in chamber 9 to occlude all air therefrom.

It is also to be noted that the air which normally bleeds into the mixing chamber through the calibrated pump discharge orifice 82, is so small in volume per unit of time that it does not affect the mixture supplied and is negligible.

It may also be noted, as the throttle valve is gradually opened beyond a position corresponding to fifty miles per hour, that the port I94 will be gradually uncovered so that the emulsion supplied to the port 39 will increase in richness as the throttle is gradually opened beyond a speed corresponding to fifty miles per hour level road car speed.

What I claim and desire to secure by Letters Patent of the United States is:

1. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet to said chamber, a mixture outlet from said chamber, a throttle controlling discharge from said outlet, a U-shaped conduit having one of the legs thereof operable to discharge fuel into said chamber, means to supply fuel to said one leg, the other leg of said conduit being open to the atmosphere, a normally open fuel jet, opening into said conduit, means to supply fuel to said jet, a valve controlling said jet, and means operable simultaneously with movement of said throttle to move said valve toward closed position to control the discharge of fuel into said chamber as said throttle is moved toward open position.

2. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet to said chamber, a mixture outlet from said chamber, a throttle controlling discharge from said outlet, a U-shaped conduit having one of the legs thereof operable to discharge fuel into said chamber, means to supply fuel to said one leg, the other leg of said conduit being open to the atmosphere, a normally open fuel jet opening into said conduit, means to supply fuel to said jet, a valve controlling said jet, and throttle-operated means operable to move said valve toward closed position to control the discharge of fuel into said chamber as said throttle is moved toward open position.

3. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet to said chamber, a mixture outlet from said chamber, a U-shaped conduit having one of the legs thereof operable to discharge fuel into said chamber, means to supply fuel to said one leg, the other leg of said conduit being open to the atmosphere, a normally open fuel jet opening into said conduit, means tosupply fuel to said jet, and means to control discharge from said jet and simultaneously to accelerate the discharge of fuel from said conduit into said chamber.-

4. A carburetor of the character described, comprising a casing having a mixing chamber, said chamber having an air inlet and main and supplemental fuel inlets, said chamber having an outlet, a throttle to control said outlet, means to supply fuel to said fuel inlets, and control neans operable upon predetermined throttle opening movement to cut off the supply of fuel to said supplemental fuel inlet and operable upon predetermined further throttle opening movement to reestablish fuel flow to said supplemental fuel inlet.

5. A carburetor ,of the character described,

comprising a casing having a mixing chamber, said chamber having an air inlet and main and supplemental fuel inlets, said chamber having an outlet, a throttle to control said outlet, means to supply fuel to said .fuel inlets, and throttle operated means operable to cut ofl the supply of fuel to said supplemental fuel inlet during a range of throttle movement between predetermined intermediatepositions of throttle opening, whereby fuel is supplied to said mixing chamber only by said main inlet during said range of movement.

6. A carburetor of the character described, comprising a casing having a mixing chamber, said chamberhavir'ig an air inlet and main and supplemental fuel inlets, said chamber having an outlet, a throttle to control said outlet, means to supply fuel to said fuel inlets, control means, operable to cut off the supply of fuel to said supplemental fuel inlet during a range of throttle movement between predetermined intermediate positions of throttle opening, means to limit the air supplied by said air inlet, and means operable when the-air supply is limited to prevent opera tion of said control means whereby fuel may be supplied from said supplemental inlet during the said range of throttle movement between predetermined intermediate positions vof throttle opening. a

7. A carburetor of the character described, comprising a casing having a mixing chamber, a mixture outlet from said chamber, a throttle to control said outlet, main fuel and air supply means opening into said chamber, supplemental fuel supply means to supply fuel to said chamber, throttle controlled means operable to cut off supply of fuel to said supplemental means upon a predetermined degree of initial throttle opening, and means operable substantially coincidentwith the operation of said throttle controlled means to accelerate the discharge of fuel from the supplemental supply means whereby the fuel mixture will have the increased proportion of fuel to air necessary for rapid acceleration.

8. A carburetor of the character described, comprising a casing having a mixing chamber, said chamber having a mixture outlet, a throttle to control said outlet, main fuel and air inlets to said chamber, supplemental fuel supply means to supply fuel to said chamber supplemental to the discharge from said main fuel inlet, means operable upon a predetermined degree of initial throttle opening to cut off supply of fuel to said supplemental means, means operable substantially coincident with said last-named means to accelerate discharge of fuel from said supplemental means, and means operable upon a predetermined degree of throttle opening to supply fuel to said supplemental means.

9. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet to said mixing chamber, a U-shaped conduit having a leg terminating in said inlet to discharge fuel to said mixing chamber, means to supply fuel to said leg, means to supply fuel to said conduit, a fuel chamber having communication with said conduit and being open to atmosphere, said fuel chamber having communication with said mixing chamber, and means to transfer fuel from said conduit to said fuel chamber for discharge into said mixing chamber.

10. A carburetor of the character described, comprising a casing having a mixing chamber, an

air inlet to said mixing chamber, a U-shaped conduit having a leg terminating in said inlet to discharge fuel to said mixing chamber, means to supply fuel to said leg, a throttle to control discharge from said mix ng chamber, means to supply fuel to said conduit, a fuel chamber having communication with said conduit and being open to atmosphere, said fuel chamber having communication with said mixing chamber, and a throttle operated pump to transfer fuel from said conduit to said fuel chamber for discharge into said mixing chamber.

l1.'A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet to said chamber, a U-shaped conduit having a leg positioned in.said air inlet to 'discharge fuel to said mixing chamber and having a plurality of atmospheric legs, means to supply fuel to said first-named leg, one of said atmospheric legs having a fuel chamber open to the atmosphere, means to supply, fuel to said conduit, a nozzle discharging from said fuel chamber into said mixing chamber, and means in another of said atmospheric legs to transfer fuel from said conduit to said fuel chamber for discharge into said mixing chamber.

12. A carburetor of the character described, comprising a casing having a mixing chamber, mixture control means, an air inlet to said chamber, a U-shaped conduit having a leg positioned in said air inlet to discharge fuel to said mixing chamber and having a plurality of atmospheric legs, means to supply fuel to said first-named leg, one of said atmospheric legs having a fuel chamber open to atmosphere, means to supply fuel to said conduit, a nozzle discharging from said fuel chamber into said mixing chamber, and means actuated by said mixture control means and positioned in another of said atmospheric legs to transfer fuel from said conduit to said fuel chamber for discharge into said mixing chamber.

13. A carburetor of the character described, comprising a casing having a mixing chamber, a throttle to control discharge from said mixing chamber, an air inlet to said chamber, a U-shaped conduit having a leg positioned in said air inlet to discharge fuel to said mixing chamber and having a plurality of atmospheric legs, one of said atmospheric legs having a fuel chamber open to atmosphere, means to supply fuel to said conduit, a fuel jet opening into said conduit, a nozzle discharging from said fuel chamber into said mixing chamber, and a throttle operated pump means in another of said atmospheric legs to transfer fuel from said conduit to said fuel chamber for discharge into said mixing chamber, said pump means controlling discharge from said fuel jet into said conduit.

14. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet passage to said chamber, a plurality of fuel inlets operable to discharge into said chamber, a fuel reservoir, means to supply fuel fromsaid reservoir to one of said fuel inlets, a pump chamber having communication with the other of said fuel inlets, a fuel inlet port to said pump chamber from said reservoir, and a piston in said pump chamber operable to discharge fuel through said other fuel inlet, said piston having control m'eans normally acting to permit fuel flow through said port into said pump chamber, said control means acting to cut off said port upon predetermined movement of said piston and to reestablish flow through said port upon further predetermined movement of said piston.

. 15. A carburetor of the character described, comprising a casing having a mixing chamber, a throttle to control discharge of mixture from said chamber, an air inlet passage to,said chamber,

a plurality of fuel inlets operable to discharge into,

predetermined movement of said piston and to J reestablish flow through said port upon further predetermined movement of said piston, and means interconnecting said throttle and said piston, said means controlling theextent of piston movement by said spring means.

16. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet passage to said chamber, a U-shaped conduit having a fuel leg discharging in said chamber and having an atmospheric leg, means to supply fuel to said conduit, an idling tube depending into said atmospheric leg, a sleeve surrounding said tube in concentric spaced relation, said sleeve being circumferentially recessed at its upper end to provide an annular fuel chamber, a nozzle communicating with said fuel chamber and discharging into said mixing chamber, and means to transfer fuel from said conduit to said fuel chamber for discharge therefrom through said nozzle by gravity and atmospheric pressure.

17. In a carburetor, a mixing chamber, air and fuel supply means for said chamber, means to increase the ratio of fuel to air supplied to said chamber, means to accelerate discharge of fuel to said chamber, and means operable upon operanamed means to render said accelerating means ineffective.

19. A carburetor of the character described,

comprising a casing having a mixing chamber with an air inlet and a plurality 'of normally open fuel inlets, a throttle controlling discharge from said chamber, means to supply fuel to said fuel inlets, control means operable upon predetermined throttle opening movement to control discharge from one of said fuel inlets, means to increase the ratio of fuel relative to air supplied to said chamber, and means operable upon operation of said last-named means to render said coninlet to said pump chamber, a valve rigid with said piston and operable on movement 'of said piston, to close said normally open fuel inlet, and

' to permit flow through said normally open inlet.

22. A carburetor of the character described, comprising a casing having a mixture passageway therethrough with air and fuel inlets and a mixture outlet, a fuel reservoir, a conduit leading from said reservoir to said passageway, a normally open valve controlling said conduit and movable to full closed positiommeans normally acting to close said conduit valve, a valve controlling said air inlet, and normally ineffective means movable into engagement with said normally acting means on movement of said air inlet valve toward closed position thereby to render said normally acting means ineffective to close said conduit valve.

23. A carburetor of the character described, comprising a casing having a mixture passageway therethrough'with air and fuel inlets and a mixture outlet, a fuel reservoir, a conduit leading from said reservoir to said passageway, a normally open valve controlling said conduit and movable to full closed position, a throttle valve controlling said outlet, means operable on opening movement of said throttle valve to move said conduit valve toward closed position, a valve controlling said air inlet, and means operable on movement of said air inlet valve toward closed position to render said last-named means ineffective to close said conduit valve.

24. A carburetor of the character described, comprising a casing having a mixture passageway therethrough with air and fuel inlets and a mixture outlet, a fuel reservoir, a conduit leading from said'reservoir to said passageway, a valve controlling said conduit and movable to full closed position, a spring normally tending to move said conduit valve toward closed position, means operable to'release said spring for valve closing movement, a valve controlling said air inlet, and meansoperable on movement of said air inlet valve toward closed position to render said first-named means ineffective to release said spring.-

25. A carburetor of the character described, comprising a casing having a mixture passageway therethrough with ainand fuel inlets and a mixture outlet, a throttle valve controlling said outlet, a fuel reservoir, a conduit leading from said reservoir to said passageway, a valve movable to full closed position and controlling said conduit, a spring operable to move said conduit valve to closed position, throttle-operated means operable to release said spring for valve closing movement, a valve controlling said air inlet, and means actuated by movement of said air inlet valve toward closed position to render said throttle operated means ineffective to release said a mixture outlet, a fuel reservoir, a conduit leading from said reservoir to saidpassageway, a.

normally open valve controlling-said conduit and movable to full closed position, means normally acting to move said conduit valve to closed position, a valve controlling said airieinlet, a cam operable by said air inlet valve, aifi'i means actuated by saidcam and operable to render said last-named means ineffective to close said conduit valve.

27. A carburetor oi the characterdescribed, comprising a casing having a mixture passageway therethrough with air and fuel inlets and a mixture outlet, a fuel reservoir, a conduit leading from said reservoir to said passageway, a normally open valve movable to full closed position and controlling said conduit, a valve having a shaft and controlling said air inlet, means normally acting to close said conduit valve, a lever movable into engagement with said normally acting means to hold said conduit valve in open position, a cam carried by said shaft aiid engageable with said lever, and means urging said lever into engagement with said cam and into holding relation' to said valve closing means whereby to move said lever into holding position on movement of said air valve toward closing position.

28. A carburetor of the character described, comprising a casing/having a mixing chamber, an air inlet passage to said chamber, a plurality of fuel inlets operable to discharge into said chamber, a fuel, reservoir, means to'supply fuel from said reservoir to one of said fuel inlets, a

fuel chamber having communication with the.

other of said fuel inlets, a fuel inlet port from said reservoir to said fuel chamber, a throttle valve controlling. discharge from said mixing chamber, a reciprocable valve movable into and through said port, and means interconnecting said valves, said reciprocable valve being normally open and being operable upon predetermined throttle opening movement to close said port, said reciprocable valve having means operable upon further throttle opening movement to reestablish flow through said port.

29. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet passage to said chamber, a plurality of fuel inlets operable to discharge into said chamber, a fuel reservoir, means to supply fuel from said reservoir to one of said fuel inlets, a fuel chamber having communication with the other of said fuel inlets, ,a fuel inlet port from said reservoir to said fuel chamber, a throttle valve controlling discharge from said mixing chamber, a valve member having a'substantially conical valve face controlling flow through said port, said valve member having a stem and being movable into and through said port, said stem having a longitudinal passageway with an inlet adjacent said valve face and an outlet spaced longitudinally therefrom, and means interconnecting said stem and said throttle valve whereby on throttle opening movement said valve member will close said port and upon further throttle opening movement said stem inlet will be moved through said port to permit flow through said stem into said fuel chamber,

30. A carburetor of the character described, comprising a casing having a mixing chamber, an air inlet passage to said chamber, a plurality of fuel inlets operable to discharge into said chamber, a fuel reservoir, means to supply fuel from said reservoir to one of said fuel inlets, a pumpchamber having communication with the other of said fuel inlets, a fuel inlet port to said pump chamber from said reservoir, a piston in through said other fuel inlet, a valve' member rigid with and projecting from said piston, said valve member being movable by said piston into i said port to cut off flow therethrough, and a by-pass passage through said valve member operable upon continued movement of said piston to reestablish flow through said port.

said pump chamber operable to discharge fuel 31. In a carburetor, a mixing chamber, main air and fuel inlets to said chamber, a valve controlling said air inlet, meansto accelerate discharge of fuel into saidchamber, and means operable upon closing movement of said air inlet valve to render said accelerating means inefiective.

WALTER H. WEBER. 

